U.S. patent application number 13/856193 was filed with the patent office on 2013-10-10 for intake system for internal combustion engine.
This patent application is currently assigned to DENSO CORPORATION. The applicant listed for this patent is DENSO CORPORATION. Invention is credited to Masao INO, Sadayuki KAMIYA, Yoshihiko SUGIURA.
Application Number | 20130263797 13/856193 |
Document ID | / |
Family ID | 49210133 |
Filed Date | 2013-10-10 |
United States Patent
Application |
20130263797 |
Kind Code |
A1 |
SUGIURA; Yoshihiko ; et
al. |
October 10, 2013 |
INTAKE SYSTEM FOR INTERNAL COMBUSTION ENGINE
Abstract
An intake system for an engine includes an intake manifold
having a surge tank room and branch passages, and a water-cooling
type cooler having a first cooling unit and second cooling units.
The surge tank room is disposed on a downstream side of a
supercharger in a flow direction of intake air. Supercharged intake
air flowing into the surge tank room is distributed among intake
ports respectively through the branch passages. The first cooling
unit is inserted in the surge tank room, and cools supercharged
intake air which has flowed into the intake manifold through heat
exchange between supercharged intake air and coolant flowing in the
first cooling unit. The second cooling units are inserted
respectively in the intake ports, and cool internal EGR gas, which
has been recirculated into their corresponding intake ports,
through heat exchange between internal EGR gas and coolant flowing
in the second cooling units.
Inventors: |
SUGIURA; Yoshihiko;
(Anjo-city, JP) ; INO; Masao; (Toyota-city,
JP) ; KAMIYA; Sadayuki; (Kariya-city, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DENSO CORPORATION |
Kariya-city |
|
JP |
|
|
Assignee: |
DENSO CORPORATION
Kariya-city
JP
|
Family ID: |
49210133 |
Appl. No.: |
13/856193 |
Filed: |
April 3, 2013 |
Current U.S.
Class: |
123/41.01 |
Current CPC
Class: |
F01P 2060/16 20130101;
F02B 29/0462 20130101; F02M 35/10222 20130101; F01P 3/00 20130101;
F02M 35/10268 20130101; F02M 35/116 20130101; Y02T 10/12 20130101;
Y02T 10/146 20130101; F01P 2060/02 20130101; F02M 26/32 20160201;
F02M 35/10032 20130101 |
Class at
Publication: |
123/41.01 |
International
Class: |
F01P 3/00 20060101
F01P003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 5, 2012 |
JP |
2012-86672 |
Claims
1. An intake system for an internal combustion engine having a
plurality of cylinders into which supercharged intake air passing
through a supercharger is introduced via a plurality of intake
ports respectively, the intake system comprising: an intake
manifold that includes: a surge tank room that is disposed on a
downstream side of the supercharger in a flow direction of intake
air; and a plurality of branch passages through which the
supercharged intake air flowing into the surge tank room is
distributed among the plurality of intake ports respectively; and a
water-cooling type cooler that includes: a first cooling unit that
is inserted and arranged in the surge tank room and that is
configured to cool the supercharged intake air which has flowed
into the intake manifold through heat exchange between the
supercharged intake air and coolant flowing in the first cooling
unit; and a plurality of second cooling units that are inserted and
arranged respectively in the plurality of intake ports and that are
configured to cool internal exhaust gas recirculation (EGR) gas,
which has been recirculated into their corresponding plurality of
intake ports, through heat exchange between the internal EGR gas
and coolant flowing in the plurality of second cooling units.
2. The intake system according to claim 1, wherein the
water-cooling type cooler is an integration of the first cooling
unit and the plurality of second cooling units.
3. The intake system according to claim 1, wherein: the
water-cooling type cooler further includes a plurality of
intermediate connection parts that respectively connect together
the first cooling unit and the plurality of second cooling units;
and the plurality of intermediate connection parts are inserted and
arranged respectively in the plurality of branch passages.
4. The intake system according to claim 1, wherein the
water-cooling type cooler further includes a plurality of tubes
that are arranged in parallel in a longitudinal direction of the
surge tank room, in a width direction of the plurality of branch
passages, and in a width direction of the plurality of intake
ports.
5. The intake system according to claim 4, wherein: the
water-cooling type cooler further includes: a coolant distribution
part that is configured to distribute coolant, which has flowed
into the water-cooling type cooler from outside, among the
plurality of tubes; and a coolant merging part that is configured
to merge together coolant from the plurality of tubes to flow the
coolant out to the outside; and the coolant distribution part and
the coolant merging part are connected to end portions of the
plurality of tubes.
6. The intake system according to claim 5, wherein the plurality of
branch passages are arranged in parallel in the longitudinal
direction of the surge tank room.
7. The intake system according to claim 5, wherein the coolant
distribution part or the coolant merging part is located on an
opposite side of the first cooling unit from the plurality of
second cooling units.
8. The intake system according to claim 4, wherein the plurality of
tubes are arranged in parallel in the longitudinal direction of the
surge tank room, in the width direction of the plurality of branch
passages, and in the width direction of the plurality of intake
ports.
9. The intake system according to claim 1, wherein the intake
manifold further includes: an opposing wall part that is opposed to
the first cooling unit with a predetermined distance between the
opposing wall part and the first cooling unit; and a surge chamber
which is located between the first cooling unit and the opposing
wall part and through which the supercharged intake air is capable
of flowing.
10. The intake system according to claim 1, wherein: the intake
manifold further includes an intake air sealing part that is in
contact with the first cooling unit; and the intake air sealing
part is configured to seal a clearance between the intake manifold
and the first cooling unit.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is based on Japanese Patent Application No.
2012-86672 filed on Apr. 5, 2012, the disclosure of which is
incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to an intake system for an
internal combustion engine in which a water-cooling type cooler is
accommodated in a surge tank room of an intake manifold and in each
intake port of the engine.
BACKGROUND
[0003] Conventional technologies will be described below.
[0004] Conventionally, in an internal combustion engine
(hereinafter referred to also as a supercharged engine) including a
supercharger that feeds supercharged intake air into cylinders,
temperature of intake air rises through its compression by the
supercharger. When the temperature of intake air rises, knocking is
easily generated at the time of high load of the engine in addition
to deterioration of filling-up efficiency of intake air with
respect to the engine. As a measure against this, there is disposed
an intercooler for cooling the supercharged intake air which has
been compressed and increased in temperature by the supercharger.
The intercooler may be of an air-cooling type or a water-cooling
type. Particularly, the water-cooling type intercooler can be
disposed in an intake pipe on a downstream side of the
supercharger, for example, in a surge tank room of an intake
manifold (see, for example, JP-T-2010-510425).
[0005] An internal exhaust gas recirculation (EGR) system that
opens an intake valve in an exhaust stroke of the engine to be
capable of returning a part of exhaust gas into an intake port is
known. Internal EGR gas which is the part of exhaust gas returned
into the intake port has higher temperature than external EGR gas.
The internal EGR gas heats the intake valve, to which fuel injected
through an injector that can inject fuel into the intake port is
easily attached, and evaporation of fuel is thereby promoted.
However, in an intake stroke immediately after being returned into
the intake port, the high-temperature internal EGR gas is drawn
into the cylinder again together with the high-temperature
supercharged intake air compressed by the supercharger.
Accordingly, the drawn internal EGR gas still has high temperature,
and temperature in a combustion chamber of each cylinder easily
rises. The high-temperature internal EGR gas flows into the
combustion chamber, and knocking may be caused when the temperature
in the combustion chamber becomes high.
[0006] For this reason, there is known an internal EGR system that
has cylinders and includes one cooling tube and cooling jackets for
cooling the internal EGR gas returned into the intake port of each
cylinder by coolant (see, for example, Japanese Patent No.
4563301). The cooling tube includes intake port insertion parts
which are inserted into vicinity of the intake valve, i.e., deep
into the intake port. The coolant flows from an inlet-side cooling
tube in a surge tank through the intake port insertion part in each
intake port in this order to cool each branch pipe of the intake
manifold and each intake port in sequence. Then, the coolant is
delivered to the outside through an outlet-side cooling tube in the
surge tank. As described above, the coolant flowing through the
cooling tube flows serially from an intake port of a cylinder #1 to
an intake port of a cylinder #4.
[0007] As regards the cooling jackets, the cooling jackets
surrounding their corresponding branch pipes are connected to one
coolant main pipe inserted into the surge tank through inlet and
outlet branch pipes. In this case as well, the coolant flows from
the cooling tube through the cooling jacket of the cylinder #1 and
is returned to the cooling tube again. The coolant flows from a
downstream side of this return part to the cooling tube through the
cooling jacket of a cylinder #2 and is returned to the cooling tube
again. The coolant flows from a downstream side of this return part
to the cooling tube through the cooling jacket of a cylinder #3 and
is returned to the cooling tube again. The coolant flows from a
downstream side of this return part to the cooling tube through the
cooling jacket of a cylinder #4 and is returned to the cooling tube
again. In this manner, the coolant flowing through each cooling
jacket flows in series from the branch pipe of the cylinder #1
toward the branch pipe of the cylinder #4.
[0008] However, in the conventional internal EGR system, both of
the supercharged intake air which has flowed into the intake
manifold and the internal EGR gas which has flowed into each intake
port are cooled by the cooling tube and the cooling jackets.
Accordingly, in the case of a four-cylinder engine, there is an
issue of deficiency in cooling performance of the supercharged
intake air and the internal EGR gas only by means of the cooling
tube for each cylinder that is divided into four quarters and the
cooling jackets.
[0009] The reason for this is that the entire flow of supercharged
intake air needs to be cooled with the volume limited. Moreover, in
order to efficiently cool the supercharged intake air, it is
necessary to expand the volume of the intercooler that is
constituted of the cooling tube and the cooling jackets. If the
intercooler is extended in an intake air flow direction (direction
X) in the intake manifold, a size of the intercooler in the
direction X is increased. If the intercooler is extended in a
height direction (direction Y) of the intake manifold that is
perpendicular to the direction X, it is necessary to increase a gap
between fastening points at which the intake manifold and a
cylinder head are fastened together. As a result of these, due to
the increase of the intercooler in size in the direction X and
direction Y, the intake manifold itself grows in size so that
installability of the intake manifold in an engine compartment of a
vehicle deteriorates.
[0010] Furthermore, in the conventional internal EGR system, the
coolant flowing through the cooling tube flows serially from the
intake port of the cylinder #1 to the intake port of the cylinder
#4. For this reason, a distance from a coolant inlet through which
the coolant flows into the cooling tube to a coolant outlet through
which the coolant flows out of the cooling tube is great in a
longitudinal direction (branch pipe arranging direction: direction
Z) of the surge tank room. Consequently, the temperature of coolant
increases for each intake port in stages through its heat exchange
with the internal EGR gas. As a result, a difference is made in
cooling performance of the internal EGR gas between the cylinders
of the engine.
SUMMARY
[0011] The present disclosure addresses at least one of the above
issues.
[0012] According to the present disclosure, there is provided an
intake system for an internal combustion engine having a plurality
of cylinders into which supercharged intake air passing through a
supercharger is introduced via a plurality of intake ports
respectively. The intake system includes an intake manifold and a
water-cooling type cooler. The intake manifold includes a surge
tank room and a plurality of branch passages. The surge tank room
is disposed on a downstream side of the supercharger in a flow
direction of intake air. The supercharged intake air flowing into
the surge tank room is distributed among the plurality of intake
ports respectively through the plurality of branch passages. The
water-cooling type cooler includes a first cooling unit and a
plurality of second cooling units. The first cooling unit is
inserted and arranged in the surge tank room, and is configured to
cool the supercharged intake air which has flowed into the intake
manifold through heat exchange between the supercharged intake air
and coolant flowing in the first cooling unit. The plurality of
second cooling units are inserted and arranged respectively in the
plurality of intake ports, and are configured to cool internal
exhaust gas recirculation (EGR) gas, which has been recirculated
into their corresponding plurality of intake ports, through heat
exchange between the internal EGR gas and coolant flowing in the
plurality of second cooling units.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The above and other objects, features and advantages of the
present disclosure will become more apparent from the following
detailed description made with reference to the accompanying
drawings. In the drawings:
[0014] FIG. 1 is a front view illustrating an intake manifold in
accordance with an embodiment;
[0015] FIG. 2 is a cross-sectional view taken along a line II-II in
FIG. 1;
[0016] FIG. 3 is a schematic view roughly illustrating a
configuration of a water-cooling type cooler according to the
embodiment;
[0017] FIG. 4 is a schematic view roughly illustrating the
configuration of the water-cooling type cooler according to the
embodiment;
[0018] FIG. 5 is a schematic view roughly illustrating the
configuration of the water-cooling type cooler according to the
embodiment; and
[0019] FIG. 6 is a front view illustrating fastening points of an
intake manifold in accordance with a comparative example.
DETAILED DESCRIPTION
[0020] An embodiment will be described in detail below with
reference to the accompanying drawings.
[0021] Configuration of an intake system for an internal combustion
engine according to the embodiment will be described.
[0022] FIGS. 1 to 5 illustrate the intake system for the engine of
the embodiment.
[0023] A control unit (engine control system) for the engine of the
present embodiment includes a supercharging system having a
turbocharger (supercharger) that supercharges (compresses or
pressurizes) intake air which has passed through an air cleaner
using the pressure of exhaust gas from the engine, and an internal
EGR system that can open an intake valve in an exhaust stroke of
the engine to recirculate a part (internal EGR gas) of the exhaust
gas into an intake passage. The control unit for the engine is used
as an intake air cooling system (intake system for the engine) that
cools the supercharged intake air (supercharged air) compressed by
a compressor of the turbocharger and the internal EGR gas by a
water-cooling type cooler. The water-cooling type cooler of the
present embodiment is accommodated to extend from a surge tank 1 of
an intake manifold to vicinity of a combustion chamber of each
cylinder in a main body of the engine so that the cooler can
efficiently cool the internal EGR gas as well as the supercharged
air.
[0024] The intake manifold of the engine includes the surge tank 1
that reduces pressure fluctuation of the supercharged air which has
flowed in from an outlet end of a throttle body, and intake air
branch pipes (hereinafter referred to as branch pipes 3) (i.e., for
each cylinder) connected respectively to communication holes 2
(i.e., for each cylinder) of this surge tank 1. A surge tank room 4
that temporarily stores the supercharged air which has flowed in
through an intake air feed port connected to the throttle body is
formed in the surge tank 1. Branch passages 5 that communicate with
the surge tank room 4 through their corresponding communication
holes 2 are formed respectively in the branch pipes 3. Details of
the intake manifold will be hereinafter described.
[0025] The engine includes cylinders (first to third cylinders:
cylinders #1 to #3). A multi-cylinder gasoline engine (inline
three-cylinder engine) that generates the output by heat energy
obtained through the combustion of air-fuel mixture of clean air
filtered through the air cleaner and fuel injected from an injector
(fuel injection valve) in the combustion chamber, is employed for
the engine. However, the engine of the embodiment is not limited to
the multi-cylinder gasoline engine, and a multi-cylinder diesel
engine may be applied to the engine. A four stroke cycle engine
that repeats four strokes of an intake stroke, compression stroke,
combustion (expansion) stroke, and exhaust stroke as a period
(cycle) is employed for the engine.
[0026] The engine includes a cylinder block in which the cylinders
are arranged in series in a cylinder arranging direction, and a
cylinder head 6 which is joined to an upper part of this cylinder
block. Three combustion chambers (cylinder bores) are formed in the
cylinder arranging direction inside the cylinder block. A piston
connected to a crankshaft (output shaft of the engine) via a
connecting rod is supported slidably in each cylinder bore in its
reciprocating direction. At least one intake port 7 that is
connected independently to the combustion chambers of the
cylinders, respectively, and at least one exhaust port (not shown)
that is connected independently to the combustion chambers of the
cylinders, respectively, are provided for the cylinder head 6. Each
intake port 7 includes a cooler accommodating space that
accommodates a cooler core 22 of the water-cooling type cooler.
Spark plugs for igniting the air-fuel mixture which has flowed into
the combustion chamber of each cylinder, and the injectors for
injecting fuel into their corresponding intake ports 7 are attached
to the cylinder head 6. In the case of an in-cylinder injection
type injector, fuel is injected into the intake air which has
flowed into the combustion chamber of each cylinder.
[0027] A coolant circuit (coolant circulation passage) that
circulation-supplies coolant to the water-cooling type cooler is
provided for the supercharged engine. The coolant circuit includes
a coolant pipe that circulation-feeds coolant from a reserve tank
into a coolant inlet pipe (coolant pipe 8) of the water-cooling
type cooler, a coolant pipe that circulation-feeds coolant from a
coolant outlet pipe (coolant pipe 9) of the water-cooling type
cooler through a radiator into the reserve tank, and a water pump
that generates a circulating flow of coolant in the coolant
circuit. Through the heat exchange between coolant and cooling wind
(outside air) in the radiator, coolant in a predetermined
temperature range (e.g., 35 to 40.degree. C.) is returned to the
reserve tank.
[0028] The water-cooling type cooler includes tubes 11, 12 arranged
in parallel and fins 13, 14 for increasing heat exchanging
efficiency between the supercharged air, internal EGR gas, and
coolant. The water-cooling type cooler is configured by stacking
the tubes 11, 12 and the fins 13, 14 alternately. This
water-cooling type cooler is obtained through integration of a
first cooler core (hereinafter referred to as a cooler core 21),
second cooler cores (hereinafter referred to as cooler cores 22),
intermediate connection parts 23, a coolant distribution part 24, a
coolant merging part 25, and a tank cap 26. Details of the
water-cooling type cooler will be hereinafter described.
[0029] Intake valves (not shown) (i.e., for each cylinder) that
open or close their corresponding intake port openings which open
into the combustion chambers of cylinders are disposed respectively
at combustion chamber-side ends of the intake ports 7. Exhaust
valves (not shown) (i.e., for each cylinder) that open or close
their corresponding exhaust port openings which open into the
combustion chambers of cylinders are disposed respectively at
combustion chamber-side ends of the exhaust ports. In the exhaust
stroke of each cylinder, the exhaust valve of each cylinder opens
at a bottom dead center (BDC), therebefore or thereafter; and the
exhaust valve of each cylinder closes at a top dead center (TDC),
therebefore or thereafter. In the intake stroke of each cylinder,
the intake valve of each cylinder opens at the top dead center
(TDC), therebefore or thereafter; and the intake valve of each
cylinder closes at the bottom dead center (BDC), therebefore or
thereafter.
[0030] In the cylinder (exhaust cylinder) in the exhaust stroke,
valve opening time of the intake valve is advanced by controlling
an intake valve timing mechanism so that valve opening periods of
the intake valve and exhaust valve overlap. Accordingly, the
internal EGR gas can be recirculated into the intake port 7 of the
exhaust cylinder. Alternatively, in the cylinder (exhaust cylinder)
in the exhaust stroke, the valve opening time of the intake valve
is advanced by controlling the intake valve timing mechanism, and
valve opening time of the exhaust valve is retarded by controlling
the exhaust valve timing mechanism so that the valve opening
periods of the intake valve and exhaust valve overlap. Accordingly,
the internal EGR gas can be recirculated into the intake port 7 of
the exhaust cylinder. The internal EGR gas returned into the intake
port 7 of the exhaust cylinder flows into the combustion chamber in
the following intake stroke. An intake pipe, in which the intake
passage is formed, is connected to the intake ports 7 that are
connected independently to the combustion chambers of the cylinders
respectively. An exhaust pipe, in which an exhaust passage is
formed, is connected to the exhaust ports that are connected
independently to the combustion chambers of the cylinders
respectively.
[0031] The intake pipe includes the compressor disposed on a
downstream side of the air cleaner, an electronic throttle disposed
on a downstream side of this compressor, and the intake manifold
connected to a downstream side of this electronic throttle. The
intake pipe is connected to the intake port 7 of each cylinder of
the engine. The exhaust pipe includes a turbine disposed on a
downstream side of an exhaust manifold, an exhaust gas purifier
(e.g., three-way catalyst) disposed on a downstream side of this
turbine, and a muffler disposed on a downstream side of this
exhaust gas purifier. The exhaust pipe is connected to the exhaust
port of each cylinder of the engine.
[0032] The turbocharger is a turbosupercharger that includes the
compressor provided in the intake passage, and the turbine provided
in the exhaust passage and that compresses the intake air flowing
through the intake passage by the compressor to feed the compressed
supercharged air into the combustion chamber of each cylinder. In
this turbocharger, upon rotation of a wheel (turbine wheel) of the
turbine by exhaust gas, a shaft coupled with the wheel to be
rotatable integrally therewith and an impeller (compressor
impeller) of the compressor are rotated, and this impeller
compresses the intake air which has passed through the air cleaner.
The turbine includes the wheel and a turbine housing. This wheel
includes turbine blades in its circumferential direction, and is
rotated by exhaust gas pressure of the engine. The compressor
includes the impeller and a compressor housing. This impeller
includes impeller blades in its circumferential direction, and is
coupled with the wheel via the shaft to be rotated (direct coupling
drive).
[0033] The electronic throttle includes the throttle body that is
joined between the compressor and the intake manifold, a throttle
valve that is accommodated rotatably in this throttle body to
adjust a flow rate of intake air, an electric actuator that opens
or closes this throttle valve, and a throttle opening sensor that
detects an opening degree (throttle opening angle) of the throttle
valve. The electric actuator includes a motor which generates power
(torque) to rotate the throttle valve upon supply of electric
power, and a deceleration mechanism that decelerates the rotation
of this motor to transmit the rotation to a rotation shaft of the
throttle valve. The motor is electrically connected to a battery
disposed in a vehicle such as an automobile, via a motor drive
circuit which is electronically controlled by an engine control
unit (electrical control unit: ECU).
[0034] Details of the intake manifold of the present embodiment
will be described with reference to FIGS. 1 to 5.
[0035] The intake manifold includes the surge tank 1 that reduces
the pressure fluctuation of the intake air (supercharged air) which
has passed through the throttle body, and the branch pipes 3
arranged in parallel in the cylinder arranging direction. Inside
the surge tank 1, there is formed the surge tank room 4 having a
predetermined internal volume that distributes the supercharged air
to the branch passages 5 which are formed respectively in the
branch pipes 3. The three communication holes 2 corresponding to
the cylinders of the three-cylinder engine respectively are intake
outlets that are formed to open at predetermined intervals (at
regular intervals) along a longitudinal direction of the surge tank
room 4. The branch pipes 3 are connected independently to their
corresponding intake ports 7 of the cylinders, and branch from the
surge tank room 4. The branch passages 5 are intake passages for
guiding the supercharged air which has flowed in from the surge
tank room 4 through the corresponding communication holes 2 into
the corresponding intake ports 7 for the cylinders.
[0036] A tumble control valve for generating a swirl flow (intake
air vortex flow, tumble flow) in the longitudinal direction in the
combustion chamber of each cylinder is integrated into the intake
manifold. The tumble control valve includes tumble valves that open
or close their corresponding branch passages 5 of the cylinders, a
shaft that is coupled with these tumble valves in synchronization
therewith, and an electric actuator that opens or closes the tumble
valves. The electric actuator includes a motor which generates
power (torque) to rotate the tumble valves upon supply of electric
power, and a deceleration mechanism that decelerates the rotation
of this motor to transmit the rotation to the shaft. The motor is
electrically connected to a battery disposed in a vehicle such as
an automobile, via a motor drive circuit which is electronically
controlled by an ECU.
[0037] The surge tank 1 includes a coupling flange (first joining
portion) 31 for fastening and fixing (joining) an outlet end part
of the throttle body by way of a fastening means such as bolts. The
intake air feed port, through which the supercharged air is
introduced from the throttle body to the surge tank room 4, is
formed in this coupling flange 31. The surge tank 1 includes a
coupling flange 32 for fastening and fixing (joining) the electric
actuator of the tumble control valve by way of a fastening means
such as bolts. A cooler attaching seat (recessed part) 33 for
fixing the water-cooling type cooler is formed through integral
moulding at a lower end portion of the surge tank 1 in FIG. 2.
[0038] On an upper end side of the surge tank 1 in FIG. 1, there
are provided coupling flanges (second joining portions) 34 that are
fastened and fixed (joined) to an inlet open end part of the
cylinder head 6 by way of a fastening means such as bolts, and bolt
fastening portions (third joining portion) 35. The coupling flanges
34 project toward the outside from both sides of the surge tank 1
in its longitudinal direction (cylinder arranging direction:
direction Z in FIG. 5). Each of the bolt fastening portions 35 is
arranged between its adjacent opposing wall parts 36 among opposing
wall parts 36 which are opposed to their respective communication
holes 2 (i.e., for each cylinder) with the surge tank room 4
therebetween. Bolt insertion holes (fastening points) 37, 38,
through which bolts screwed into bolt fastening holes of the
cylinder head 6 are inserted, are formed respectively in the
coupling flanges 34 and the bolt fastening portions 35. A pipe
joint 39 for attaching a pipe for blow-by gas reduction, and a pipe
joint 40 for attaching a negative pressure introduction pipe
through which intake air negative pressure is supplied to a brake
booster are provided for the surge tank 1 to project laterally from
an outer surface of the surge tank 1.
[0039] The surge tank 1 includes an opposing wall part 41 that is
opposed to the cooler core 21 of the water-cooling type cooler with
a predetermined distance therebetween; and an opposing wall part 42
that is opposed to the coolant distribution part 24 which is an
inlet tank part of the water-cooling type cooler and the coolant
merging part 25 which is an outlet tank part of the cooler or that
is opposed to the cooler core 21 of the water-cooling type cooler
with a predetermined distance therebetween. The opposing wall parts
41, 42 include an intake air sealing part (a sealing member 43 and
a rib 44) that is in contact with the cooler core 21 to seal a
clearance between the cooler core 21 and the opposing wall parts
41, 42. The rib 44 projects from the opposing wall part 41 toward
an upstream end face of the cooler core 21. The communication holes
2 (i.e., for each cylinder) pass through the opposing wall part 42
to communicate respectively with the branch passages 5.
[0040] The surge tank room 4 includes the cooler accommodating
space that accommodates the cooler core 21, a surge chamber 45 that
is located on an upstream side of this cooler accommodating space,
and a surge chamber 46 that is located on a downstream side of the
cooler accommodating space. The surge chamber 45 is a predetermined
volume space that is formed between the cooler core 21 and the
opposing wall part 41. In this surge chamber 45, the supercharged
air can flow in the longitudinal direction of the surge tank room 4
(direction Z in FIGS. 3 and 5). The surge chamber 46 is a
predetermined volume space formed between the cooler core 21 and
the opposing wall part 42. In this surge chamber 46, the
supercharged air can flow in the longitudinal direction of the
surge tank room 4 (direction Z in FIGS. 3 and 5). The branch
passages 5 respectively include cooler accommodating spaces that
accommodate the corresponding intermediate connection parts 23.
Hooks 47, 48 for attaching (or hooking or bundling) another
component (engine auxiliary machinery or wire harness) are provided
for the surge tank 1 of the intake manifold. A grid-like
reinforcing rib 49 extending in a direction Y in FIGS. 4 and 5 and
in the direction Z in FIGS. 3 and 5 is provided on the outer
surface of the surge tank 1.
[0041] Details of the water-cooling type cooler of the present
embodiment will be described with reference to FIGS. 1 to 5.
[0042] The water-cooling type cooler is a U-turn flow type
intercooler and EGR cooler for cooling both of the supercharged air
and the internal EGR gas through the heat exchange of the
high-temperature supercharged air and the high-temperature internal
EGR gas with the coolant. The water-cooling type cooler is a heat
exchanger for exchanging heat between the supercharged air and
internal EGR gas flowing outside the tubes 11, 12 and the coolant
flowing inside the tubes 11, 12.
[0043] The water-cooling type cooler includes the cooler core 21
that is inserted and arranged in the cooler accommodating space of
the surge tank 1, the cooler cores 22 that are inserted and
arranged respectively in the cooler accommodating spaces of the
cylinder head 6, and the intermediate connection parts 23 that are
inserted and arranged correspondingly in the respective cooler
accommodating spaces of the branch pipes 3. The water-cooling type
cooler includes the coolant distribution part 24 that distributes
the coolant which has flowed in from the outside (reserve tank)
through the coolant pipe 8 among the tubes 11, 12 which constitute
the cooler cores 21, 22; and the coolant merging part 25 that
merges together the coolant to flow the coolant out from the tubes
11, 12 through the coolant pipe 9 to the outside (radiator). The
coolant pipes 8, 9 are provided at the tank cap 26 that covers each
opening of the coolant distribution part 24 and the coolant merging
part 25. These coolant pipes 8, 9 project toward the outside of the
surge tank 1 through the cooler attaching seat 33. The tank cap 26
is held on the cooler attaching seat 33.
[0044] The tubes 11, 12 are tubes (flat tubes) having flat shapes
that are configured by joining together a pair of molded plates
(metal materials) through brazing so that coolant passages through
which the coolant flows are formed between opposed surfaces (inner
wall surfaces) of the pair of molded plate. Inside each of the
tubes 11, 12, there are provided a coolant passage 51 which is a
forward passage, a coolant passage 52 which is a return passage, a
U-shaped part (coolant passage 53) that connects together these
coolant passage 51 and coolant passage 52, and a center partition
54 that divides the coolant passage 51 from the coolant passage 52.
The fins 13, 14 are obtained by forming a thin belt-like metal
plate into predetermined shapes. Louvers (not shown) for improving
heat exchanging efficiency are formed at parts of these fins 13, 14
on their both sides in the thickness direction by which the
supercharged air flows (hereinafter referred to as supercharged air
passages). A fin (corrugated fin) having a corrugated shape that is
excellent in performance of cooling of the supercharged air and
internal EGR gas is used for each of the fins 13, 14.
Alternatively, a plate fin may be used for each of the fins 13, 14.
Moreover, a corrugated fin and plate fin may be used in combination
for each of the fins 13, 14.
[0045] The cooler cores 21, 22 respectively include side plates for
reinforcing the cooler cores 21, 22 further outward of outermost
fins 13, 14 that are arranged on both outermost sides in a tube
stacking direction (the longitudinal direction of the surge tank
room 4, or a width direction of the intake ports 7: direction Z in
FIGS. 3 and 5) as a result of stacking the tubes 11, 12 and the
fins 13, 14 alternately. Accordingly, the side plates extending in
a direction that is parallel to a longitudinal direction of the
tubes 11, 12 (direction Y in FIGS. 4 and 5, direction X in FIGS. 3
and 4) are arranged respectively on both end sides of the cooler
cores 21, 22 in the tube stacking direction. The side plates are
connected respectively to the outermost fins 13, 14 on both sides
to constitute reinforcing members for keeping high the strength of
the cooler cores 21, 22.
[0046] The cooler core 21 includes the tubes 11, 12 that are
arranged in parallel in the longitudinal direction of the surge
tank room 4 at predetermined intervals (at regular intervals), and
the fins 13 that are arranged between their adjacent tubes 11, 12.
The cooler core 21 constitutes a first cooling unit (supercharged
intake air cooling unit, heat exchanger main body) that cools the
supercharged air which has flowed into the surge tank room 4 of the
surge tank 1 through its heat exchange with the coolant flowing in
each of the coolant passages 51, 52 of the tubes 11, 12. This
cooler core 21 is disposed to cover the entire passage cross
section of the surge tank room 4 in its longitudinal direction. The
cooler core 22 includes the tubes 11 that are arranged in parallel
in the width direction of the intake ports 7 at predetermined
intervals (at regular intervals), and the fins 14 that are arranged
between their adjacent tubes 11. The cooler core 22 constitutes a
second cooling unit (internal EGR cooling unit, heat exchanger main
body) that cools the internal EGR gas which has flowed into each
intake port 7 of the cylinder head 6 through its heat exchange with
the coolant flowing in each of the coolant passages 51 to 53 of the
tubes 11. This cooler core 22 is disposed to cover the entire
passage cross section of each intake port 7 in its width direction.
The intermediate connection part 23 is a junction part that
includes the tubes 11, 12 arranged in parallel in the longitudinal
direction of the surge tank room 4 at predetermined intervals (at
regular intervals) and that connects together the cooler core 21
and the cooler core 22. The tubes 11, 12 which constitute the
intermediate connection part 23 respectively include bent parts 55
that are bent perpendicularly because the branch passages 5 are
crooked. The coolant distribution part 24 and the coolant merging
part 25 are concentratedly arranged at end parts (one end parts) of
the tubes 11, 12 on the opposing wall part 41-side, and are
connected to one end parts of the tubes 11, 12. The coolant
distribution part 24 and the coolant merging part 25 are located on
a different (opposite) side of the cooler core 21 of the
water-cooling type cooler from the cooler core 22.
[0047] The tubes 11, 12 include plural (three) long tube groups 11a
to 11c that pass from the surge tank room 4 through the branch
passages 5 and reach the intake ports 7, and plural (two) short
tube groups 12a, 12b that remain in the surge tank room 4. The long
tube groups 11a to 11c include the coolant passages 51, each of
which extends from the coolant distribution part 24 through the
surge tank room 4, its corresponding communication hole 2, and its
corresponding branch passage 5 to the vicinity of a rear side of
its corresponding intake port 7 (vicinity of intake valve); the
coolant passages 52, each of which extends from the vicinity of a
rear side of its corresponding intake port 7 (vicinity of intake
valve) through its corresponding branch passage 5, its
corresponding communication hole 2, and the surge tank room 4 to
the coolant merging part 25; and the coolant passages 53, each of
which connects together the ends of its corresponding coolant
passages 51, 52. Accordingly, the U-shaped coolant passages 51 to
53 are formed respectively in the tubes 11 which constitute the
long tube groups 11a to 11c. The short tube groups 12a, 12b include
the coolant passages 51, each of which extends from the coolant
distribution part 24 through the surge tank room 4 to the vicinity
of the inner wall surface of the opposing wall part 42; the coolant
passages 52, each of which extends from the vicinity of the inner
wall surface of the opposing wall part 42 through the surge tank
room 4 to the coolant merging part 25; and the coolant passages 53,
each of which connects together the ends of its corresponding
coolant passages 51, 52. Accordingly, the U-shaped coolant passages
51 to 53 are formed respectively in the tubes 12 which constitute
the short tube groups 12a, 12b.
[0048] Operation of the intake air cooling system of the present
embodiment will be described briefly with reference to FIGS. 1 to
5.
[0049] First, the internal EGR gas that has flowed back
(recirculated) into the intake port 7 of the exhaust cylinder by
opening the intake valve in the exhaust stroke in which the exhaust
valve opens, is distributed among the supercharged air passages
defined between the adjacent tubes 11, 12 of the water-cooling type
cooler. The internal EGR gas distributed among the supercharged air
passages is cooled through its heat exchange with the coolant
circulating through the coolant passages 51 to 53 of the tubes 11
which constitute the cooler core 22. The supercharged air, which
has been compressed by the compressor of the turbocharger to have
high temperature, flows into the surge chamber 45 of the surge tank
1 of the intake manifold to be distributed among the supercharged
air passages defined between the adjacent tubes 11, 12 of the
water-cooling type cooler. The supercharged air distributed among
the supercharged air passages is cooled through its heat exchange
with the coolant circulating through the coolant passages 51, 52 of
the tubes 11, 12 which constitute the cooler core 21.
[0050] The cooled supercharged air flows from each supercharged air
passage into the surge chamber 46 to be distributed to the branch
passage 5 that communicates with the communication hole 2 of an
intake cylinder in which the intake valve is opened. The
supercharged air, which has flowed from the branch passage 5 of the
intake cylinder into the intake port 7, is fed into the combustion
chamber of the intake cylinder together with the internal EGR gas
which has been returned into the intake port 7 and cooled.
Accordingly, the high-temperature internal EGR gas flows into the
combustion chamber of each cylinder to make avoidable a defect of
temperature rise in the combustion chamber. Thus, generating of
knocking can be limited. In addition, the amount of emission of
nitrogen oxides (NOx) contained in the exhaust gas discharged from
the combustion chamber of each cylinder can be limited.
[0051] Effects of the embodiment will be described below.
[0052] As described above, in the intake air cooling system of the
present embodiment, the cooler core 21 of the water-cooling type
cooler is inserted and arranged in the surge tank room 4 of the
surge tank 1, and the cooler cores 22 are inserted and arranged
respectively in the intake ports 7. Accordingly, the number of
components and assembly man-hours can be reduced to reduce costs of
the entire system. Moreover, the water-cooling type cooler which is
obtained by the integration of the cooler cores 21, 22, the
intermediate connection part 23, the coolant distribution part 24,
and the coolant merging part 25 is integrated into the surge tank
1, the respective branch pipes 3 and the cylinder head 6.
Accordingly, the number of components and assembly man-hours can be
reduced to reduce the costs.
[0053] Furthermore, the supercharged air and internal EGR gas can
be efficiently cooled by the coolant flowing in the tubes 11, 12
which constitute the cooler cores 21, 22. Accordingly, cooling
performance of the supercharged air and the internal EGR gas can be
improved without causing growth in size of the intake manifold and
the water-cooling type cooler and deterioration in their
installability. Additionally, the long tube groups 11a to 11c
(i.e., for each cylinder) are arranged in parallel in the
longitudinal direction of the surge tank room 4 and in the width
direction of the intake ports 7 (direction Z in FIGS. 3 and 5).
More specifically, the tubes 11 are arranged in parallel from the
intake port 7 of the cylinder #1 through the intake port 7 of the
cylinder #3. Accordingly, the coolant distributed from the coolant
distribution part 24 among the tubes 11 can flow in parallel from
the intake port 7 of the cylinder #1 to the intake port 7 of the
cylinder #3. As a result, a difference (variation) in cooling
performance of the internal EGR gas between the cylinders of the
engine can be curbed.
[0054] Moreover, there are provided the tubes 11, 12 that are
arranged in parallel in the longitudinal direction of the surge
tank room 4, in the width direction of the branch passages 5 and in
the width direction of the intake ports 7. Accordingly, even though
the tubes 11, 12 are made as two kinds: the long tube groups 11a to
11c and the short tube groups 12a, 12b to have such shapes that
bypass (avoid) the bolt insertion holes (fastening points) 37, 38
between the surge tank 1 of the intake manifold and the cylinder
head 6 of the engine, the respective coolant passages 51 to 53 of
the tubes 11, 12 are easily set. Therefore, the tubes 11, 12 are
produced to have two types: the long tube groups 11a to 11c which
extend into the respective intake ports 7, and the short tube
groups 12a, 12b which end in the surge tank 1. Consequently, the
tubes 11, 12 can be arranged in parallel in the longitudinal
direction of the surge tank room 4 (direction Z in FIGS. 3 and 5).
As a result, the gaps between the bolt insertion holes 37, 38 do
not need to be increased, which has the advantage that a constrain
condition for designing the engine main body is not created. As
illustrated in FIG. 6, if tubes 101 are arranged in parallel in a
length direction of the surge tank room (direction Y in FIGS. 4 and
5), the tubes 101 interfere with the fastening points, so that it
is difficult to attach an intake manifold to an engine main body
(e.g., cylinder head).
[0055] Furthermore, there is set the surge chamber 46 in which the
supercharged air can flow at a position opposed to the coolant
distribution part 24 and the coolant merging part 25 of the
water-cooling type cooler, or between a downstream end face of the
cooler core 21 and the opposing wall part 42 of the surge tank 1.
Accordingly, the entire cooler core 21 in the surge tank 1 can be
used as a portion for cooling the supercharged air. As a result,
the supercharged air cooled by the entire cooler core 21 flows into
the cooler cores 22 in their respective intake ports 7 through the
branch passages 5. Thus, an increase in size of the surge tank room
4 in its height direction (direction X in FIGS. 3 and 4) can be
prevented. Without this surge chamber 46, the entire cooler core 21
cannot be used along the entire longitudinal direction of the surge
tank room 4.
[0056] Additionally, there are provided the rib 44 that projects
from the inner wall surface of the opposing wall part 41 of the
surge tank 1 to be in contact with the upstream end face of the
cooler core 21; and the sealing member 43 for sealing the clearance
between the upstream end face of the cooler core 21 and the end
surface of the rib 44. Accordingly, the supercharged air which has
flowed into the surge chamber 45 does not flow preferentially
toward the cooler cores 22, and the entire supercharged air flows
through the supercharged air passages of the cooler core 21.
Therefore, the performance in cooling the supercharged air can be
improved. If the intake air sealing part (the sealing member 43,
the rib 44) is not provided, because of intake air resistance, the
supercharged air which has flowed into the surge chamber 45 flows
into the cooler cores 22 without passing through the supercharged
air passages of the cooler core 21, so that the performance in
cooling the supercharged air is decreased.
[0057] Modifications to the above embodiment will be described
below.
[0058] In the present embodiment, the water-cooling type cooler is
accommodated in the intake manifold. Alternatively, a function of
an air-cooling type cooler may be used in combination by
configuring the intake manifold from a metal material, and by
providing a fin for releasing the heat to outside air (cooling
wind) on the outer surface of the intake manifold. The coolant may
flow into the water-cooling type cooler through the coolant pipe 9,
and may flow out of the water-cooling type cooler through the
coolant pipe 8.
[0059] In the present embodiment, the water-cooling type cooler
which is accommodated in the intake manifold and the engine main
body (cylinder head 6) is used as the water-cooling type
intercooler (cooler core 21) for cooling the supercharged air, and
the water-cooling type internal EGR cooler (cooler core 22) for
cooling the internal EGR gas. Alternatively, the water-cooling type
cooler may be used as not only the water-cooling type intercooler
(cooler core 21) and the water-cooling type internal EGR cooler
(cooler core 22) as but also a water-cooling type external EGR
cooler (cooler core) for cooling external EGR gas. Moreover, the
coolant circulating through the coolant circuit (including the
reserve tank, the water pump, and the radiator) that is provided
exclusively for cooling the supercharged air and internal EGR gas
is used for the coolant. Alternatively, coolant circulating through
an engine coolant circuit (including a water jacket, a water pump
and a radiator) for cooling the engine main body (the cylinder
block and the cylinder head 6) may be used. Furthermore, another
cooling medium (liquid) such as cooling oil may be used for the
coolant.
[0060] In addition, not only the multi-cylinder gasoline engine but
also a multi-cylinder diesel engine may be used for the internal
combustion engine disposed in a vehicle such as an automobile
(e.g., a driving source of a generator, compressor, blower, for
example, or an engine for vehicle traveling). The turbocharger is
used for a supercharger. However, a supercharger, electric
supercharger, or electric compressor may also be used. The hooks
47, 48 and the reinforcing rib 49, which are arranged for the
intake manifold, do not necessarily be provided. The surge tank 1
and the branch pipes 3 may be separately configured.
[0061] To sum up, the intake system for the engine of the above
embodiment can be described as follows.
[0062] According to the first aspect of the disclosure, there is
provided the water-cooling type cooler that cools the supercharged
intake air through heat exchange between the coolant flowing
through the inside of the first cooling unit 21, and the
supercharged intake air which has flowed into the intake manifold
1, 3; and that cools the internal EGR gas through heat exchange
between the coolant flowing inside the second cooling units 22, and
the internal EGR gas which has been recirculated into the
corresponding intake ports 7. The first cooling unit 21 is inserted
and arranged in the surge tank room 4 of the intake manifold 1, 3;
and the second cooling units 22 are inserted and arranged
respectively in the intake ports 7 of the engine. Accordingly, the
number of components and attachment man-hours can be reduced, which
leads to the cost reduction. Moreover, the supercharged intake air
which has flowed into the intake manifold 1, 3 is cooled by the
coolant flowing inside the first cooling unit 21 of the
water-cooling type cooler; and the internal EGR gas which has
returned into the intake port 7 for each cylinder is cooled by the
coolant flowing through the inside of the second cooling unit 22 of
the water-cooling type cooler. As a result, cooling performance of
the supercharged intake air and the internal EGR gas can be
improved without causing growth in size of the intake manifold 1, 3
and the water-cooling type cooler and deterioration in their
installability. In addition, a difference in cooling performance of
the internal EGR gas between the cylinders can be limited.
[0063] According to the second aspect of the disclosure, there is
provided the water-cooling type cooler, i.e., the integration of
the first cooling unit 21 that cools the supercharged intake air
which has flowed into the intake manifold 1, 3; and the second
cooling units 22 that cool the internal EGR gas which has been
recirculated into the corresponding intake ports 7. Accordingly,
the number of components and attachment man-hours can be reduced,
which leads to the cost reduction. According to the third aspect of
the disclosure, there is provided the water-cooling type cooler
including the intermediate connection parts 23 that connect
together the first cooling unit 21 and the second cooling units 22.
The intermediate connection parts 23 are inserted and arranged
respectively in the branch passages 5 of the intake manifold 1, 3.
Accordingly, the first cooling unit 21 and the second cooling units
22 can be combined together.
[0064] According to the fourth aspect of the disclosure, the
water-cooling type cooler including the tubes 11, 12 which are
arranged in parallel in the longitudinal direction of the surge
tank room 4, in the width direction of the branch passages 5, and
in the width direction of the intake ports 7 exchanges heat between
the supercharged intake air or internal EGR gas flowing outside the
tubes 11, 12, and the coolant flowing inside the tubes 11, 12.
According to the fifth aspect of the disclosure, there is provided
the water-cooling type cooler including the coolant distribution
part 24 that distributes the coolant, which has flowed in from the
outside, among the tubes 11, 12; and the coolant merging part 25
that merges together the coolant from the tubes 11, 12 to flow the
coolant out to the outside. The coolant distribution part 24 and
the coolant merging part 25 are connected to the ends of the tubes
11, 12.
[0065] According to the eighth aspect of the disclosure, there are
provided the tubes 11, 12 which are arranged in parallel in the
longitudinal direction (direction Z) of the surge tank room 4, in
the width direction (direction Z) of the branch passages 5 and in
the width direction (direction Z) of the intake ports 7.
Accordingly, even though two types (11a to 11c; and 12a, 12b) of
the tubes are produced to have the shapes to avoid the fastening
points 37, 38 between the intake manifold 1, 3 and the engine, the
flows of the coolant in the tubes 11, 12 can be set. Thus, the two
types of the tubes 11, 12: those reaching into the intake ports 7
and those ending inside the intake manifold 1, 3 are made, and the
tubes 11, 12 can thereby be arranged in the longitudinal direction
of the surge tank room 4. Furthermore, by arranging the tubes 11,
12 in the direction Z, the coolant can flow in parallel, so that a
difference is not made in cooling performance between the
cylinders.
[0066] According to the ninth aspect of the disclosure, the surge
chamber 45, 46 through which the supercharged intake air can flow
is set between the first cooling unit 21 and the opposing wall part
41, 42. Accordingly, the entire first cooling unit 21 in the intake
manifold 1, 3 can be used as a unit for cooling the supercharged
intake air. As a result, the supercharged intake air which has been
cooled by the entire first cooling unit 21 can flow into the second
cooling unit 22 in each intake port 7. Therefore, the increase in
size of the surge tank room 4 in its height direction can be
prevented. According to the tenth aspect of the disclosure, there
is provided the intake manifold 1, 3 including the intake air
sealing part 43, 44 that is in contact with the first cooling unit
21 for sealing a clearance between the first cooling unit 21 and
the intake manifold 1, 3. As described above, by providing the
intake air sealing part 43, 44 in the intake manifold 1, 3 on the
upstream side of the first cooling unit 21 in the intake air flow
direction, the supercharged intake air which has flowed into the
intake manifold 1, 3 does not flow preferentially toward the second
cooling units 22, and flows toward the first cooling unit 21, so
that performance in cooling the supercharged intake air can be
improved.
[0067] While the present disclosure has been described with
reference to embodiments thereof, it is to be understood that the
disclosure is not limited to the embodiments and constructions. The
present disclosure is intended to cover various modification and
equivalent arrangements. In addition, while the various
combinations and configurations, other combinations and
configurations, including more, less or only a single element, are
also within the spirit and scope of the present disclosure.
* * * * *